checking for nice... ../zsh-4.0/configure: Can't reopen pipe to command substitution (fd 4): No child processes
yes
checking for wctomb... ../zsh-4.0/configure: Can't reopen pipe to command substitution (fd 4): No child processes
no
I reran it from scratch after removing config.cache and the error went away.
So I suspect some transient thing, but I thought I'd see whether this rings
a bell with anyone.